German Patent DE 36 32 418 on the one hand describes a vibration damper whose mass body is attached directly in a hollow drive shaft by way of a rubber spring element which envelops it radially. Also described is a second vibration damper whose mass body is mounted in a sleeve by way of a rubber spring element which also envelops it. The sleeve is embedded in an elastic layer.
The vibration dampers described there, also called cancelers, are installed principally in propeller shafts or propeller shaft tubes. The propeller shaft tubes are loaded on the one hand in torsion by the drive torque, and on the other hand in bending by their own weight and by the mass effect. They must therefore be not only sufficiently stiff in torsion, but also as light as possible. In order for the vibration dampers with their mass bodies to increase the overall weight of the propeller shaft tube as little as possible, the vibration dampers must be capable of being arranged at the optimum point. That point is, for example, the vibration crest of an interfering vibration that is to be canceled.
At the optimum point, the weight of the mass body can have its minimal value.
Since each propeller shaft, as a flexurally elastic rotor, generally exhibits some imbalance as a result, inter alia, of manufacturing tolerances, the centrifugal force also increases with rotation speed. The propeller shaft thus deflects in the direction of the eccentricity of its center of gravity. In the lower range of rotation speeds usual for propeller shafts, the propeller shaft deflection initially rises in proportion to the centrifugal force component, which is related only to the eccentricity in the center of gravity because the centrifugal force component related to the shaft deflection is still small. Above half the deflection-critical rotation speed, the shaft deflection component quickly increases to a multiple of the component of the eccentricity of the center of gravity. In this range, the known rubber-sprung mass bodies can dangerously amplify the imbalance of the entire structure due to an eccentric displacement in the direction of the eccentricity in center of gravity of the propeller shaft.
Also known, from United Kingdom Patent No. GB 2 073 363 A, is a printing roller in which a rubber-sprung mass body is mounted. For this purpose, the mass body is arranged by way of two rubber rings in a sleeve press-fit into the printing roller. The rubber rings sit at the two free ends of the mass body. Arranged next to each rubber ring is a metal ring which limits the radial deflection of the mass body.